1. Field of the Invention
The present invention generally relates to a bearing and seal assembly for supporting and sealing end portions of a rotatable paddle shaft in a mortar mixer or a mixer for similar abrasive materials and the like. More specifically, the bearing and seal assembly of the present invention represents an improvement over the bearing and seal assembly disclosed in U.S. Pat. No. 3,932,006, owned by the assignee of the present application.
2. Description of the Prior Art
U.S. Pat. No. 3,932,006, issued Jan. 13, 1976, discloses a paddle shaft bearing and seal assembly supporting the ends of the pivotal mixer drum and supporting and sealing the paddle shaft ends which extend through openings in the end walls of the mixer drum. The mortar or similar abrasive material being mixed in the drum has a tendency to cause wear and deterioration of the seal assembly with resultant migration of the abrasive material into the interior of the bearing and seal housing and into the bearings thus causing rapid wear of the bearings.
As disclosed in the aforementioned patent, each bearing and seal housing is welded or otherwise permanently attached to the outside surface of the mixer drum end wall. In use of the bearing and seal assemblies disclosed in the above patent, the mixer usually is operated until the seal subassemblies became worn and fail permitting mortar or similar abrasive material to cause wear of the bearings and ultimate seizure of the paddle shaft. In some instances, this seizure requires that the paddle shaft be cut to facilitate removal of the paddle shaft from the drum and subsequent removal of the bearing and seal assemblies to enable replacement. The prior U.S. patents cited in the specification of the above patent and the prior art cited in the “references cited” section of the above patent also disclose various bearing and seal structures for various rotatable components including seals for use in mixers.
Prior commercial mortar mixers with rotating paddle shafts also include some paddle shaft bearing and seal assemblies in which the housings are removable. However, such assemblies do not include a simple and effective bearing and seal assembly which can be easily lubricated or a removable bearing and seal housing which can be readily removed from the end wall of the drum. The prior art also does not utilize a removable bearing and seal housing supporting the bearing and seal subassemblies in a spaced relation with the bottom of the bearing and seal housing in alignment with the space between the bearing and seal subassemblies having a downwardly directed opening. Such an opening allows abrasive material which migrates past the seal subassembly to fall through the opening prior to such material reaching the bearings thereby increasing the life expectancy of the bearings and alerting the operator to seal failure which enables replacement of the bearing and seal assembly prior to the bearings failing due to contamination by the abrasive material migrating past the seal subassembly.